1. Technical Field
The present invention relates to a physical quantity sensor, an electronic device, and a moving object.
2. Related Art
In recent years, a physical quantity sensor for detecting a physical quantity such as acceleration has been developed by using silicon micro electro mechanical systems (MEMS), for example.
The physical quantity sensor, for example, includes a substrate, a fixed electrode portion fixed to the substrate, and a movable body including a movable electrode portion disposed to oppose the fixed electrode portion, and detects the physical quantity such as acceleration based on electrostatic capacitance between the movable electrode portion and the fixed electrode portion.
In the physical quantity sensor, the movable body may be stuck to the substrate due to the movable body being pulled to the substrate side by the electrostatic force, due to generation of a difference in potential between the movable body and the substrate, when manufacturing the physical quantity sensor, for example. Particularly, when performing anode bonding of a cover (cap) and the substrate for sealing the movable body, a great difference in potential is generated between the movable body and the substrate.
In order to prevent the movable body from being stuck to the substrate, U.S. Pat. No. 7,121,141 Specification, for example, discloses a physical quantity sensor which comes in contact with a shield before a fixed electrode comes in contact with a movable body (test mass).
However, in the technology disclosed in U.S. Pat. No. 7,121,141 Specification, since the substrate is exposed in an area between two fixed electrodes, the movable body may be stuck to the substrate due to an electrostatic force between the area to which the substrate is exposed and the movable body. Particularly, in the physical quantity sensor disclosed in U.S. Pat. No. 7,121,141 Specification, since the area to which the substrate is exposed opposes a torsion bar having low rigidity, the movable body may be easily stuck to the substrate.